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Add --unwindlib=[libgcc|compiler-rt] to parallel --rtlib= [take 2]
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"clang++ hello.cc --rtlib=compiler-rt"

now can works without specifying additional unwind or exception
handling libraries.

This reworked version of the feature no longer modifies today's default
unwind library for compiler-rt: which is nothing. Rather, a user
can specify -DCLANG_DEFAULT_UNWINDLIB=libunwind when configuring
the compiler.

This should address the issues from the previous version.

Update tests for new --unwindlib semantics.

Differential Revision: https://reviews.llvm.org/D59109

llvm-svn: 356508
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@Sterling-Augustine
Sterling-Augustine committed Mar 19, 2019
1 parent 7742391 commit 6271606
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Showing 8 changed files with 186 additions and 35 deletions.
18 changes: 18 additions & 0 deletions clang/CMakeLists.txt
View file
Expand Up @@ -266,6 +266,24 @@ if (NOT(CLANG_DEFAULT_RTLIB STREQUAL "" OR
"Default runtime library to use (\"libgcc\" or \"compiler-rt\", empty for platform default)" FORCE)
endif()

set(CLANG_DEFAULT_UNWINDLIB "" CACHE STRING
"Default unwind library to use (\"none\" \"libgcc\" or \"libunwind\", empty to match runtime library.)")
if (CLANG_DEFAULT_UNWINDLIB STREQUAL "")
if (CLANG_DEFAULT_RTLIB STREQUAL "libgcc")
set (CLANG_DEFAULT_UNWINDLIB "libgcc" CACHE STRING "" FORCE)
elseif (CLANG_DEFAULT_RTLIBS STREQUAL "libunwind")
set (CLANG_DEFAULT_UNWINDLIB "none" CACHE STRING "" FORCE)
endif()
endif()

if (NOT(CLANG_DEFAULT_UNWINDLIB STREQUAL "none" OR
CLANG_DEFAULT_UNWINDLIB STREQUAL "libgcc" OR
CLANG_DEFAULT_UNWINDLIB STREQUAL "libunwind"))
message(WARNING "Resetting default unwindlib to use platform default")
set(CLANG_DEFAULT_UNWINDLIB "" CACHE STRING
"Default unwind library to use (\"none\" \"libgcc\" or \"libunwind\", empty for none)" FORCE)
endif()

set(CLANG_DEFAULT_OBJCOPY "objcopy" CACHE STRING
"Default objcopy executable to use.")

Expand Down
4 changes: 4 additions & 0 deletions clang/include/clang/Basic/DiagnosticDriverKinds.td
View file
Expand Up @@ -51,6 +51,10 @@ def err_drv_invalid_rtlib_name : Error<
"invalid runtime library name in argument '%0'">;
def err_drv_unsupported_rtlib_for_platform : Error<
"unsupported runtime library '%0' for platform '%1'">;
def err_drv_invalid_unwindlib_name : Error<
"invalid unwind library name in argument '%0'">;
def err_drv_incompatible_unwindlib : Error<
"--rtlib=libgcc requires --unwindlib=libgcc">;
def err_drv_invalid_stdlib_name : Error<
"invalid library name in argument '%0'">;
def err_drv_invalid_output_with_multiple_archs : Error<
Expand Down
3 changes: 3 additions & 0 deletions clang/include/clang/Config/config.h.cmake
View file
Expand Up @@ -23,6 +23,9 @@
/* Default runtime library to use. */
#define CLANG_DEFAULT_RTLIB "${CLANG_DEFAULT_RTLIB}"

/* Default unwind library to use. */
#define CLANG_DEFAULT_UNWINDLIB "${CLANG_DEFAULT_UNWINDLIB}"

/* Default objcopy to use */
#define CLANG_DEFAULT_OBJCOPY "${CLANG_DEFAULT_OBJCOPY}"

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2 changes: 2 additions & 0 deletions clang/include/clang/Driver/Options.td
View file
Expand Up @@ -2591,6 +2591,8 @@ def std_EQ : Joined<["-", "--"], "std=">, Flags<[CC1Option]>,
}]>;
def stdlib_EQ : Joined<["-", "--"], "stdlib=">, Flags<[CC1Option]>,
HelpText<"C++ standard library to use">, Values<"libc++,libstdc++,platform">;
def unwindlib_EQ : Joined<["-", "--"], "unwindlib=">, Flags<[CC1Option]>,
HelpText<"Unwind library to use">, Values<"libgcc,unwindlib,platform">;
def sub__library : JoinedOrSeparate<["-"], "sub_library">;
def sub__umbrella : JoinedOrSeparate<["-"], "sub_umbrella">;
def system_header_prefix : Joined<["--"], "system-header-prefix=">,
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14 changes: 14 additions & 0 deletions clang/include/clang/Driver/ToolChain.h
View file
Expand Up @@ -99,6 +99,12 @@ class ToolChain {
RLT_Libgcc
};

enum UnwindLibType {
UNW_None,
UNW_CompilerRT,
UNW_Libgcc
};

enum RTTIMode {
RM_Enabled,
RM_Disabled,
Expand Down Expand Up @@ -369,6 +375,10 @@ class ToolChain {
return ToolChain::CST_Libstdcxx;
}

virtual UnwindLibType GetDefaultUnwindLibType() const {
return ToolChain::UNW_None;
}

virtual std::string getCompilerRTPath() const;

virtual std::string getCompilerRT(const llvm::opt::ArgList &Args,
Expand Down Expand Up @@ -513,6 +523,10 @@ class ToolChain {
// given compilation arguments.
virtual CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const;

// GetUnwindLibType - Determine the unwind library type to use with the
// given compilation arguments.
virtual UnwindLibType GetUnwindLibType(const llvm::opt::ArgList &Args) const;

/// AddClangCXXStdlibIncludeArgs - Add the clang -cc1 level arguments to set
/// the include paths to use for the given C++ standard library type.
virtual void
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27 changes: 27 additions & 0 deletions clang/lib/Driver/ToolChain.cpp
View file
Expand Up @@ -693,6 +693,33 @@ ToolChain::RuntimeLibType ToolChain::GetRuntimeLibType(
return GetDefaultRuntimeLibType();
}

ToolChain::UnwindLibType ToolChain::GetUnwindLibType(
const ArgList &Args) const {
const Arg *A = Args.getLastArg(options::OPT_unwindlib_EQ);
StringRef LibName = A ? A->getValue() : CLANG_DEFAULT_UNWINDLIB;

if (LibName == "none")
return ToolChain::UNW_None;
else if (LibName == "platform" || LibName == "") {
ToolChain::RuntimeLibType RtLibType = GetRuntimeLibType(Args);
if (RtLibType == ToolChain::RLT_CompilerRT)
return ToolChain::UNW_None;
else if (RtLibType == ToolChain::RLT_Libgcc)
return ToolChain::UNW_Libgcc;
} else if (LibName == "libunwind") {
if (GetRuntimeLibType(Args) == RLT_Libgcc)
getDriver().Diag(diag::err_drv_incompatible_unwindlib);
return ToolChain::UNW_CompilerRT;
} else if (LibName == "libgcc")
return ToolChain::UNW_Libgcc;

if (A)
getDriver().Diag(diag::err_drv_invalid_unwindlib_name)
<< A->getAsString(Args);

return GetDefaultUnwindLibType();
}

ToolChain::CXXStdlibType ToolChain::GetCXXStdlibType(const ArgList &Args) const{
const Arg *A = Args.getLastArg(options::OPT_stdlib_EQ);
StringRef LibName = A ? A->getValue() : CLANG_DEFAULT_CXX_STDLIB;
Expand Down
104 changes: 69 additions & 35 deletions clang/lib/Driver/ToolChains/CommonArgs.cpp
View file
Expand Up @@ -1159,47 +1159,80 @@ bool tools::isObjCAutoRefCount(const ArgList &Args) {
return Args.hasFlag(options::OPT_fobjc_arc, options::OPT_fno_objc_arc, false);
}

static void AddLibgcc(const llvm::Triple &Triple, const Driver &D,
ArgStringList &CmdArgs, const ArgList &Args) {
bool isAndroid = Triple.isAndroid();
bool isCygMing = Triple.isOSCygMing();
bool IsIAMCU = Triple.isOSIAMCU();
bool StaticLibgcc = Args.hasArg(options::OPT_static_libgcc) ||
Args.hasArg(options::OPT_static) ||
Args.hasArg(options::OPT_static_pie);

bool SharedLibgcc = Args.hasArg(options::OPT_shared_libgcc);
bool UnspecifiedLibgcc = !StaticLibgcc && !SharedLibgcc;

// Gcc adds libgcc arguments in various ways:
//
// gcc <none>: -lgcc --as-needed -lgcc_s --no-as-needed
// g++ <none>: -lgcc_s -lgcc
// gcc shared: -lgcc_s -lgcc
// g++ shared: -lgcc_s -lgcc
// gcc static: -lgcc -lgcc_eh
// g++ static: -lgcc -lgcc_eh
// gcc static-pie: -lgcc -lgcc_eh
// g++ static-pie: -lgcc -lgcc_eh
//
// Also, certain targets need additional adjustments.
enum class LibGccType { UnspecifiedLibGcc, StaticLibGcc, SharedLibGcc };

static LibGccType getLibGccType(const ArgList &Args) {
bool Static = Args.hasArg(options::OPT_static_libgcc) ||
Args.hasArg(options::OPT_static) ||
Args.hasArg(options::OPT_static_pie);

bool Shared = Args.hasArg(options::OPT_shared_libgcc);
if (Shared)
return LibGccType::SharedLibGcc;
if (Static)
return LibGccType::StaticLibGcc;
return LibGccType::UnspecifiedLibGcc;
}

bool LibGccFirst = (D.CCCIsCC() && UnspecifiedLibgcc) || StaticLibgcc;
if (LibGccFirst)
CmdArgs.push_back("-lgcc");
// Gcc adds libgcc arguments in various ways:
//
// gcc <none>: -lgcc --as-needed -lgcc_s --no-as-needed
// g++ <none>: -lgcc_s -lgcc
// gcc shared: -lgcc_s -lgcc
// g++ shared: -lgcc_s -lgcc
// gcc static: -lgcc -lgcc_eh
// g++ static: -lgcc -lgcc_eh
// gcc static-pie: -lgcc -lgcc_eh
// g++ static-pie: -lgcc -lgcc_eh
//
// Also, certain targets need additional adjustments.

static void AddUnwindLibrary(const ToolChain &TC, const Driver &D,
ArgStringList &CmdArgs, const ArgList &Args) {
ToolChain::UnwindLibType UNW = TC.GetUnwindLibType(Args);
// Targets that don't use unwind libraries.
if (TC.getTriple().isAndroid() || TC.getTriple().isOSIAMCU() ||
TC.getTriple().isOSBinFormatWasm() ||
UNW == ToolChain::UNW_None)
return;

bool AsNeeded = D.CCCIsCC() && UnspecifiedLibgcc && !isAndroid && !isCygMing;
LibGccType LGT = getLibGccType(Args);
bool AsNeeded = D.CCCIsCC() && LGT == LibGccType::UnspecifiedLibGcc &&
!TC.getTriple().isAndroid() && !TC.getTriple().isOSCygMing();
if (AsNeeded)
CmdArgs.push_back("--as-needed");

if ((UnspecifiedLibgcc || SharedLibgcc) && !isAndroid)
CmdArgs.push_back("-lgcc_s");

else if (StaticLibgcc && !isAndroid && !IsIAMCU)
CmdArgs.push_back("-lgcc_eh");
switch (UNW) {
case ToolChain::UNW_None:
return;
case ToolChain::UNW_Libgcc: {
LibGccType LGT = getLibGccType(Args);
if (LGT == LibGccType::UnspecifiedLibGcc || LGT == LibGccType::SharedLibGcc)
CmdArgs.push_back("-lgcc_s");
else if (LGT == LibGccType::StaticLibGcc)
CmdArgs.push_back("-lgcc_eh");
break;
}
case ToolChain::UNW_CompilerRT:
CmdArgs.push_back("-lunwind");
break;
}

if (AsNeeded)
CmdArgs.push_back("--no-as-needed");
}

static void AddLibgcc(const ToolChain &TC, const Driver &D,
ArgStringList &CmdArgs, const ArgList &Args) {
bool isAndroid = TC.getTriple().isAndroid();

LibGccType LGT = getLibGccType(Args);
bool LibGccFirst = (D.CCCIsCC() && LGT == LibGccType::UnspecifiedLibGcc) ||
LGT == LibGccType::StaticLibGcc;
if (LibGccFirst)
CmdArgs.push_back("-lgcc");

AddUnwindLibrary(TC, D, CmdArgs, Args);

if (!LibGccFirst)
CmdArgs.push_back("-lgcc");
Expand All @@ -1209,7 +1242,7 @@ static void AddLibgcc(const llvm::Triple &Triple, const Driver &D,
//
// NOTE: This fixes a link error on Android MIPS as well. The non-static
// libgcc for MIPS relies on _Unwind_Find_FDE and dl_iterate_phdr from libdl.
if (isAndroid && !StaticLibgcc)
if (isAndroid && getLibGccType(Args) != LibGccType::StaticLibGcc)
CmdArgs.push_back("-ldl");
}

Expand All @@ -1221,6 +1254,7 @@ void tools::AddRunTimeLibs(const ToolChain &TC, const Driver &D,
switch (RLT) {
case ToolChain::RLT_CompilerRT:
CmdArgs.push_back(TC.getCompilerRTArgString(Args, "builtins"));
AddUnwindLibrary(TC, D, CmdArgs, Args);
break;
case ToolChain::RLT_Libgcc:
// Make sure libgcc is not used under MSVC environment by default
Expand All @@ -1232,7 +1266,7 @@ void tools::AddRunTimeLibs(const ToolChain &TC, const Driver &D,
<< Args.getLastArg(options::OPT_rtlib_EQ)->getValue() << "MSVC";
}
} else
AddLibgcc(TC.getTriple(), D, CmdArgs, Args);
AddLibgcc(TC, D, CmdArgs, Args);
break;
}
}
Expand Down
49 changes: 49 additions & 0 deletions clang/test/Driver/compiler-rt-unwind.c
View file
@@ -0,0 +1,49 @@
// General tests that the driver handles combinations of --rtlib=XXX and
// --unwindlib=XXX properly.
//
// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
// RUN: --target=x86_64-unknown-linux \
// RUN: --gcc-toolchain="" \
// RUN: | FileCheck --check-prefix=RTLIB-EMPTY %s
// RTLIB-EMPTY: "{{.*}}lgcc"
// RTLIB-EMPTY: "{{.*}}-lgcc_s"
//
// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
// RUN: --target=x86_64-unknown-linux -rtlib=libgcc \
// RUN: --gcc-toolchain="" \
// RUN: | FileCheck --check-prefix=RTLIB-GCC %s
// RTLIB-GCC: "{{.*}}lgcc"
// RTLIB-GCC: "{{.*}}lgcc_s"
//
// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
// RUN: --target=x86_64-unknown-linux -rtlib=libgcc --unwindlib=libunwind \
// RUN: --gcc-toolchain="" \
// RUN: | FileCheck --check-prefix=RTLIB-GCC-UNWINDLIB-COMPILER-RT %s
// RTLIB-GCC-UNWINDLIB-COMPILER-RT: "{{.*}}lgcc"
// RTLIB-GCC-UNWINDLIB-COMPILER-RT: "{{.*}}lunwind"
//
// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
// RUN: --target=x86_64-unknown-linux -rtlib=compiler-rt \
// RUN: --gcc-toolchain="" \
// RUN: | FileCheck --check-prefix=RTLIB-COMPILER-RT %s
// RTLIB-COMPILER-RT: "{{.*}}libclang_rt.builtins-x86_64.a"
//
// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
// RUN: --target=x86_64-unknown-linux -rtlib=compiler-rt --unwindlib=libgcc \
// RUN: --gcc-toolchain="" \
// RUN: | FileCheck --check-prefix=RTLIB-COMPILER-RT-UNWINDLIB-GCC %s
// RTLIB-COMPILER-RT-UNWINDLIB-GCC: "{{.*}}libclang_rt.builtins-x86_64.a"
// RTLIB-COMPILER-RT-UNWINDLIB-GCC: "{{.*}}lgcc_s"
//
// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
// RUN: --target=x86_64-unknown-linux -rtlib=compiler-rt --unwindlib=libgcc \
// RUN: -static --gcc-toolchain="" \
// RUN: | FileCheck --check-prefix=RTLIB-COMPILER-RT-UNWINDLIB-GCC-STATIC %s
// RTLIB-COMPILER-RT-UNWINDLIB-GCC-STATIC: "{{.*}}libclang_rt.builtins-x86_64.a"
// RTLIB-COMPILER-RT-UNWINDLIB-GCC-STATIC: "{{.*}}lgcc_eh"
//
// RUN: not %clang -no-canonical-prefixes %s -o %t.o 2> %t.err \
// RUN: --target=x86_64-unknown-linux -rtlib=libgcc --unwindlib=libunwind \
// RUN: --gcc-toolchain="" \
// RUN: FileCheck --input-file=%t.err --check-prefix=RTLIB-GCC-UNWINDLIB-COMPILER_RT %s
// RTLIB-GCC-UNWINDLIB-COMPILER_RT: "{{[.|\\\n]*}}--rtlib=libgcc requires --unwindlib=libgcc"

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